Iatrogenic Dural Arteriovenous Fistula Formation As a Rare Complication of External Ventricular Drain Placement: Institutional Review of 16 Cases.

INTRODUCTION:External ventricular drain (EVD) placement is a life-saving neurosurgical procedure used to divert cerebrospinal fluid and reduce intracranial pressure in conditions such as subarachnoid hemorrhage, intraparenchymal hemorrhage, and intraventricular hemorrhage. While known complications include infection and hemorrhage, the formation of iatrogenic dural arteriovenous fistulas (dAVFs) following ventriculostomy is under-reported. METHODS:We conducted a retrospective review of patients at our institution from 2002 to 2023 who developed dAVFs after EVD placement. Inclusion criteria required angiographic confirmation of a new dAVF near the EVD site. Demographics, primary pathology, EVD characteristics, angiographic findings, treatment approach, and outcomes were recorded. RESULTS:Sixteen patients met the inclusion criteria. Subarachnoid hemorrhage was the most common indication for EVD placement (75.0%). All drains were placed at Kocher's point, most commonly on the right (75.0%). All dAVFs involved the middle meningeal artery, with venous drainage documented in 93.8%-most frequently into the middle meningeal vein (80.0%). Eight patients (50.0%) underwent treatment, primarily with ethanol embolization (62.5%). All treated cases achieved radiographic cure without complications. Two patients experienced spontaneous resolution. Three patients were managed conservatively for low-risk fistulas and five were lost to follow-up. CONCLUSION:This study presents the largest institutional series to date of iatrogenic dAVFs following ventriculostomy. While rare, iatrogenic dAVFs have the potential for significant morbidity if they develop complications from venous hypertension and may require additional treatments. Our findings highlight the need for awareness of identifying and appropriately managing ventriculostomy-related dAVFs.